import {Injectable} from '@angular/core';
import {InMemoryDbService} from 'angular-in-memory-web-api';
import {Hero} from './hero';

//模拟数据的服务，需要继承InMemoryDbService接口
@Injectable({
    providedIn: 'root',
})
export class InMemoryDataService implements InMemoryDbService {
    createDb() {
        const heroes = [
            {id: 11, name: 'Mr. Nice'},
            {id: 12, name: 'Narco'},
            {id: 13, name: 'Bombasto'},
            {id: 14, name: 'Celeritas'},
            {id: 15, name: 'Magneta'},
            {id: 16, name: 'RubberMan'},
            {id: 17, name: 'Dynama'},
            {id: 18, name: 'Dr IQ'},
            {id: 19, name: 'Magma'},
            {id: 20, name: 'Tornado'},
        ];
        return {heroes};
    }

    //重载该方法以保证每个英雄都有一个id
    // Overrides the genId method to ensure that a hero always has an id.
    // If the heroes array is empty,
    // the method below returns the initial number (11).
    // if the heroes array is not empty, the method below returns the highest
    // hero id + 1.
    genId(heroes: Hero[]): number {
        return heroes.length > 0 ? Math.max(...heroes.map(hero => hero.id)) + 1 : 11;
    }
}
